When elephants want to make a decision, they "rumble," producing a low-pitched gurgling noise that sounds like a truck rolling down a distant road. That's the conclusion of researchers who have been watching and listening to the animals for 20 years. This audio file represents a conversation between males deciding to depart from a watering hole. Curious about these vocalizations, researchers studying African elephant communication in Namibia had set up observation sites at five watering holes in Etosha National Park and analyzed 14 bouts of calling by the elephants. When it's time to move on, typically three of about 20 elephants in the group discuss the decision, Caitlin O'Connell-Rodwell, a behavioral ecologist at Stanford University in Palo Alto, California, and colleagues report this month in Bioacoustics. One elephant, the leader, starts off with a 3-second rumble, immediately followed by a response from another and then another, most likely the other dominant individuals in the group. This measured two- or three-way conversation lasts several minutes, then the whole group leaves. "It's kind of like a committee making a decision," says O'Connell-Rodwell, who observed this behavior in family groups and bonded males but not among strangers. "It demonstrates there's a very coordinated organized structure."
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